Diseases & Conditions

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Scoliosis is a condition that causes the spine to curve sideways. Neuromuscular scoliosis (NMS) is a type of scoliosis that can occur in children who have medical conditions that impair their ability to control the muscles that support the spine. A few of the more common conditions associated with NMS include muscular dystrophy, cerebral palsy, and spina bifida.

Because children with NMS can have a range of medical issues in addition to the spinal curve, treatment involves a team of doctors and health professionals from different medical specialties working together to provide care. In many cases of NMS, surgery is needed to correct the curvature and stabilize the spine.

Instead of a straight line down the back, a spine with scoliosis curves. (Left) Normal spine anatomy. (Right) Scoliosis can make the spine look more like the letters "C" or "S." Neuromuscular spinal curves are typically long and involve the entire spine.

Description

Scoliosis causes the small bones of the spine to tilt and/or rotate so that instead of a straight line down the middle of the back, the spine looks more like the letter "C" or "S."

NMS is just one type of scoliosis that can affect children and adolescents. The other main types include:

Idiopathic scoliosis. This is the most common type of scoliosis and often shows up in children when they reach puberty. "Idiopathic" means that the exact cause of the condition is not known.

Congenital scoliosis. This type of scoliosis develops before birth. Babies with congenital scoliosis may have spinal bones that are not fully formed or are fused together.

In all types of scoliosis, spinal curves often become larger and more noticeable during periods of rapid growth, such as during adolescence. Idiopathic and congenital scoliosis curves typically affect limited sections of the spine and stop progressing when an adolescent is full-grown. In contrast, NMS spinal curves often develop at a younger age than idiopathic scoliosis. These curves typically are long and involve the entire spine. In addition, NMS curves progress more rapidly and may continue to worsen even into adulthood.

Cause

NMS is caused by an underlying medical condition that affects either the body's neurological system or muscular system—or a combination of both. The likelihood of developing a spinal curve corresponds with the extent of nerve and muscle involvement associated with a child's neuromuscular condition.

Although not all children with neuromuscular conditions develop NMS, it is quite common — particularly in children whose condition requires them to use wheelchairs. With some neuromuscular conditions, a child may be able to walk when young, but may need to use a wheelchair upon reaching adolescence. This marks the time when these patients are at greatest risk for developing NMS or for having an existing curve progress, primarily because this time often coincides with a major growth spurt.

The table below shows how the incidence of scoliosis increases according to the neuromuscular involvement of the underlying condition.

Symptoms

For NMS patients who are able to walk (ambulators), the signs of NMS are similar to those of children with idiopathic scoliosis:

Tilted, uneven shoulders, with one shoulder blade protruding more than the other

Prominence of the ribs on one side

Uneven waistline

One hip higher than the other

For children who use wheelchairs (and who are generally more severely involved), spinal curves may cause changes in appearance like those described above, as well as changes that can hinder daily functions:

A change in overall posture, such as slouching or leaning more to one side

Tilted pelvis (called pelvic obliquity)

A deteriorating ability to sit and the need to use the hands and arms for seating support

Pressure sores (decubitus ulcers) may develop due to the pelvic tilt and overall imbalance

These changes can further impede a child's independence, making activities of daily living, like dressing and eating, more difficult.

In addition, children with NMS may also have other types of spinal curves, such as kyphosis (hunchback) or lordosis (swayback). Larger scoliosis curves in the upper back or hyperlordotic curves (excessive swayback) may reduce the space in the chest for the lungs and cause breathing problems.

Doctor Examination

Physical Examination

Before the physical examination, your doctor will discuss your child's family and medical histories and overall health. He or she will want to know what symptoms are present and when they began.

During the physical exam, your doctor will conduct a visual inspection of your child's back and spine. In addition, he or she will assess any problems with sitting balance, skin breakdown, or daily function.

(Left) This adolescent girl with cerebral palsy uses a wheelchair and has a large sweeping curve to the left. (Right) Her x-ray shows a pelvic tilt, which may cause sitting imbalance and lead to pressure sores.

Courtesy Texas Scottish Rite Hospital for Children

Imaging Tests

X-rays. To help doctors assess the severity of NMS, spinal curves are measured using x-ray images. X-rays provide clear images of dense structures such as bone. An x-ray will allow your doctor to see the location of the curve on the spine and to measure the degree of the curvature.

Magnetic resonance imaging (MRI) scans. These tests provide clear images of soft tissues and help the doctor to evaluate the health of the spinal cord.

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Treatment

A multidisciplinary approach is needed in the treatment of neuromuscular scoliosis. The treatment team may include specialists in orthopaedics, pediatrics, pulmonology, neurology, urology, nutrition, and gastroenterology. Coordination of care is very important and will help ensure that every aspect of treatment is maximized. In many cases, the NMS treatment team is led by the child's developmental pediatrician.

Treatment for NMS will depend on your child's age and underlying condition, as well as the type and severity of the spinal curve.

Nonsurgical Treatment

Although nonsurgical treatments will not prevent your child's curve from progressing, they may delay the progression and help improve function and quality of life. Nonsurgical treatments include:

Wheelchair modification. This is the most commonly recommended nonsurgical treatment. If your child has a shifted pelvis that affects balance, his or her wheelchair can be modified to improve posture. These modifications may include custom-molded chair backings and adjustment of the side positioners to help improve balance while sitting.

Bracing. For some patients in wheelchairs, wearing a molded plastic brace around the upper body may be recommended to provide a more stable sitting position and allow for use of the arms and hands. However, bracing will not prevent the progression of NMS curves like it can in idiopathic scoliosis.

For NMS patients who are able to walk, wearing a brace may make them more likely to fall or lose their balance while walking — especially if they have significant muscle weakness, pulmonary problems, or an unsteady gait.

Surgical Treatment

Indications for surgery. Your child's treatment team will consider several things when determining whether to recommend surgery to control the spinal curve, including how severe the curve is and how much it affects your child's function. The most common indications for surgery include:

Curves greater than 50 degrees (in patients who are still growing)

Curves greater than 50 degrees that have progressed more than 10 degrees (in patients who have reached skeletal maturity)

Difficulty sitting and functional deterioration

Pain

Problems with heart or lung function

The decision to proceed with surgery in the noncommunicative patient is often very difficult and relies on the size of the spinal curve, the impact of the curve on sitting balance, and the care of the patient. Input from the family and/or caregiver is critical in this decision process.

Because NMS results from an underlying neuromuscular condition, the underlying condition guides the treatment strategy. For example, neurosurgical decompression—a surgery that involves removal of inflamed, ingrown, or compressed tissues within the spine—may prevent curve progression in patients with syringomyelia (a fluid sac within the spinal cord), diastematomyelia (bone or cartilage ingrowth into the spinal cord), or tethered cord syndrome. These patients may then not need spinal stabilization.

Surgical stabilization of the spine. The goals of this treatment are to:

Stabilize the curve and stop its progression

Balance the spine and pelvis, thereby increasing sitting tolerance if the patient is in a wheelchair or improving walking if the patient can walk

Improve lung function

Reduce pain

Growing Rods. Most operations to stabilize the spine also stop growth in the segment of the spine that is operated on. Temporary spinal stabilization with growing rods may be necessary in young children to allow the spine, chest, and lungs to grow as much as possible. The goal of a growing rod is to allow continued growth while correcting the curve and improving daily function.

During the procedure, one or two rods are attached to the spine above and below the curve. Every 6 to 8 months, the child returns to the doctor for a minor procedure to lengthen the rod(s) to keep up with the child's growth. When the child is fully grown, the rod(s) are replaced and a spinal fusion is performed.

Growing rods can stabilize the spine and also allow for continued spine and chest wall growth. (Left) This side-view of the spine shows how the rods are fixed into the upper and lower vertebrae with screws. (Right) This illustration shows how the growing rods are placed in the spine during the surgery. Also shown are the surgical instruments used to hold back the skin and soft tissues to allow the surgeon to access the spine.

Reproduced from Akbarnia BA, Blakemore LC, Campbell RM, Dormans JP: Approaches for the very young child with spinal deformity: what's new and what works. Instr Course Lect 2010; 59:407-424.

Spinal Fusion. Spinal fusion is the most common surgical procedure used to treat NMS.

During the procedure, the curved vertebrae are fused together so that they heal into a single, solid fusion (bone mass). This will stop the growth completely in the abnormal segment of the spine and prevent the curve from worsening in the future.

Small pieces of bone graft are placed between the vertebrae to be fused to promote ("glue") the fusion. These graft pieces are from a bone bank or made from an artificial material. Over time, the bone grows together—similar to when a broken bone heals.

Metal rods are typically used to hold the spine in place until the fusion happens. The rods are attached to the spine by hooks, screws, and/or wires. Once the bone graft fuses with existing bone, the straightened spine does not move and the curve will not progress.

In patients who are still very immature and growing rapidly, spinal fusion may require both an anterior (front) and posterior (back) approach. This two-sided approach can help to avoid "crankshaft syndrome," a problem in which areas of the spine that are still growing continue to rotate, while the instrumented areas remain fixed.

Because patients in wheelchairs often also have a pelvic tilt, it is common for the fusion to extend from the upper thoracic spine down to the sacrum and pelvis.

(Left) This patient with cerebral palsy has a large spinal curve to the left. (Right) The spine has been stabilized by two rods and multiple screws, bringing the curve to a more normal alignment.

Courtesy Scottish Rite Hospital for Children

Complications

Because NMS is associated with other underlying neuromuscular disorders and because surgery for NMS typically involves more levels of the spine, the complication rate after surgery is higher than with some other types of scoliosis. Your doctor will talk with you about potential complications and the steps taken prior to surgery to prevent them. For example, your treatment team will work to maximize nutrition and cardiopulmonary status prior to surgery to minimize the risk of infection and prolonged need for being on the ventilator after surgery. Similarly, before surgery your child's skin in the region of the spine and pelvis will be fully assessed to minimize the risk for infection.

The Pediatric Orthopaedic Society of North America (POSNA) is a group of board eligible/board certified orthopaedic surgeons who have specialized training in the care of children's musculoskeletal health.

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AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS Find an Orthopaedist program on this website.